1. Field of the Invention
The present invention relates to a cover-type endoscope apparatus for inserting a covering endoscope into an endoscope cover.
2. Description of the Related Art
Recently, endoscopes have been widely used in the medical field. Such an endoscope used in the medical field sometimes cannot provide a sufficiently observable image, when inserted into a living body, because an observing window provided at a distal end of the inserting portion may be smudged by the mucus of a diseased part. Therefore, the endoscope is constructed to have air-supplying/water-supplying functions for supplying water to the observing window for washing and blowing out the residual water by supplying air thereto, by an operation at the proximal side of the endoscope. Further, this air-supplying function can also be used for supplying air into a body cavity to enable easy observation of the portion of interest. The air and the water are supplied through an air supplying duct line or a water supplying duct line.
Other types of endoscopes include one having an aspiratory duct line for aspirating and discharging unnecessary mucus, and one having a forceps channel (treatment channel) to enable sampling a tissue by means of a biopsy forceps or therapeutic treatment using a treatment equipment.
Such endoscopes for the medical field, once used for a patient, would be subject to a washing or sterilizing process for securely preventing any infection.
However, a significant amount of time is required to complete the washing or sterilizing operation, thereby degrading the handling property and use efficiency of the endoscope.
In particular, since the aforementioned duct lines communicate to the outside of the living body from a distal end opening portion opened to a body cavity of the patient through the duct lines of the inserting portion, the distal end opening portion and the inside of the duct lines should also be washed and sterilized. This operation requires a significant amount of time and is troublesome.
Therefore, in recent years, there has been used one kind of an endoscope apparats, a so-called "cover-type" endoscope, in which the endoscope itself is covered with an endoscope cover which is thrown away after every use, thereby simplifying the washing and sterilizing processes.
According to this cover-type endoscope, a duct line opened in a body cavity of a patient is provided at the endoscope cover side, while an observing means not opened to the body cavity of the patient and an illuminating means are provided at the endoscope side to be covered with the endoscope cover. As a result, the video endoscope is not left unclean even when using a quite expensive video endoscope incorporating a solid imaging device (SID) capable of easily displaying the image on a monitor by excellent properties of the illuminating means, high image quality and demonstrating characteristics. Further, it is possible to simplify the washing and sterilizing processes by dumping the endoscope cover.
This so-called cover-type endoscope is disclosed in U.S. Pat. No. 4,646,722 or U.S. Pat. No. 3,162,190, for example.
There are a great number of kinds of endoscopes since the outer diameter, length, field of view of the inserting portion of the endoscope are determined in accordance with the function and the diseased part of interest. Therefore, it is almost impossible to include all desirable features of an endoscope to be used. In particular, in a cover-type endoscope apparatus used as a combination of a covering endoscope and an endoscope cover, it is necessary to select a proper endoscope cover which would fit the respective covering endoscope each time. If the selected combination is improper, the essential functions of the endoscope cannot be sufficiently and totally brought out.
Further, such a cover-type endoscope is used for inspection, by fitting the endoscope cover to a covering endoscope for preventing inter-patients or inter-hospital infections. Therefore, a soiled, used endoscope cover is thrown away upon completion of an inspection for mounting a new one for the next case. However, it is not easy to distinguish between a used cover and an unused one, which requires a significant amount of time and labor.
On the other hand, a proximal (hand-side) end portion of water-supplying/air-supplying duct lines, an aspiratory duct line and the like provided at the endoscope cover side is coupled to an external connecting device (fluid controlling device) through a connecting portion. The external connecting device is provided with a pump and an electromagnetic valve for air-supplying, water-supplying and aspirating in response to an operation of a switch mounted on an operational portion side of the endoscope. However, the air is a compressible fluid while the liquid is an incompressible fluid, and it is necessary to set the inner diameters of the duct lines to proper sizes for obtaining a correct flow amount in view of the flow resistance of the respective duct line. Therefore, it is typical, for example, to have the inner diameter of the air-supplying duct line different from that of the water-supplying duct line.
The endoscope cover is selected in accordance with the covering endoscope to be used, so that the connection of the duct line with the external connecting device would be made by the user. At this time, if the user erroneously connects, for example, the air-supplying duct line instead of the water-supplying duct line to the device, the fluid being water or air would be supplied through a duct line of unsuitable inner diameter. Namely, if air is supplied through a water-supplying duct line, the supplied amount of air would become excessive. Meanwhile, if water is supplied through the air-supplying duct line, the desired amount of water cannot be obtained, thereby impeding the inspection. The same problem would arise when the aspiratory duct line is erroneously connected to the device.